Variables:
A data frame with 83 observations on the following 5 variables.
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age
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a numeric vector
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deaths
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number of deaths, D_k, among people of age k, a numeric vector
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number
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size of the population, P_k surviving until this age, a numeric vector
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ratio
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the ratio P_{k+1}/P_k, the conditional probability of surviving until age k + 1 given that one had already reached age k, a numeric vector
Details
Halley's table contained only age and number. For people aged over 84 years, Halley just noted that their total number was 107. This value is not included in the data set.
The data from Breslau had a mean of 1,238 births per year: this is the value that Halley took for the size, P_0 of the population cohort at age 0. From the data, he could compute the annual mean D_k of the number of deaths among people aged k for all k >= 0. From this, he calculated the number P_{k+1} surviving one more year,
P_{k+1} = P_k - D_k
This method had the great advantage of not requiring a general census but only knowledge of the number of births and deaths and of the age at which people died during a few years.